Welcome to the Community! I really appreciate that you are taking security seriously!
It is not possible to turn off data logging by default for new scenarios.
This setting applies to each scenario individually.
Make treats security with the highest importance and this setting really means a no-log policy, so enabling it by default would make creating scenarios extremely difficult for users.
If you set Data is confidential to yes - Make will not store anything related to your logs and business data.
Keep in mind that this will make debugging of the scenario very limited.
To enable this setting, click on Scenario setting (gear icon) and set Data is confidental to Yes.
If you are looking for enhanced security of your Make account- you should take Enterprise plan under consideration.
To discuss details contact Make directly or you can talk to any official Make.com partners.
There is no such feature in Make yet—I’m sure others will agree that this would be nice to have too!
If this is important to you, please submit this suggestion to the Idea exchange, under Platform Ideas and Improvements. However, do search for a similar request first (and also upvote), just in case it has already been suggested to avoid duplicates.
— @samliew P.S.: investing some effort into the tutorials in the Make Academy will save you lots of time and frustration using Make!